The present invention relates to an intake sound reduction device that reduces an intake sound of an internal combustion engine, and more particularly to an intake sound reduction device having an elastically deformable bellows volume chamber.
Japanese Unexamined Patent Publication No. 2013-124599 (hereinafter is referred to as “JP2013-124599”) discloses an intake sound reduction device for an internal combustion engine, which is a new type of intake sound reduction device proposed by an applicant of the present invention. This intake sound reduction device is configured so that a volume chamber is defined by an elastic member formed by an elastically deformable bellows, and this volume chamber is connected to an intake duct of the internal combustion engine via a communication pipe that is a main pipe of Helmholtz resonant element. The elastic member is accommodated in a cylindrical case that is open to the air.